The WM8900 device's quiescent headphone playback power consumption is less than 6 mW in voice mode and less than 11 mW in Hi-Fi mode. This extends battery life in portable audio applications and improves the quiescent power consumption of many feature-rich multimedia codecs with ground-referenced headphone outputs by up to 25%, according to Wolfson. When using a typical 300 mAH battery, a WM8900-based design can extend battery life by up to 11 hours during headphone music playback at a typical 2 mW/ch listening level.

The WM8900 addresses cost and board space issues by implementing ground-referenced headphone outputs that remove the need for bulky DC blocking capacitors, said Wolfson. The device is offered in a low-profile 0.55-mm high 40-pin QFN package, which makes the WM8900 well suited for slim, portable electronic applications.

The WM8900 Class G architecture is implemented by powering the headphone amplifier with a dual input, level shifting, intelligent charge pump. The charge pump generates both the positive and negative power supply rails, ground referencing the headphone outputs. Automatic control of the charge pump is said to maintain the most power efficient operating state during headphone playback. This is done with no intervention required from the operator or host software.

The ground-referenced Class G headphone amplifier also eliminates many sources of pops and clicks during power up, power down, mute and un-mute to deliver high-quality audio performance.